Summary: mbt repeat
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The function of this repeat is unknown, but is found in a number of nuclear proteins such as drosophila sex comb on midleg protein Q9VHA0. The repeat is found in up to four copies as in Q9UHJ3. The repeat contains a completely conserved glutamate at its amino terminus that may be important for function.
Bornemann D, Miller E, Simon J; , Genetics 1998;150:675-686.: Expression and properties of wild-type and mutant forms of the Drosophila sex comb on midleg (SCM) repressor protein. PUBMED:9755199 EPMC:9755199
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR004092
The function of the malignant brain tumor (MBT) repeat is unknown, but is found in a number of nuclear proteins involved in transcriptional repression. The repeat contains a completely conserved glutamate at its amino terminus that may be important for function.
The crystal structure of the two MBT repeats of human SCM-like 2 protein has been reported. Each repeat consists of an extended "arm" and a globular core. The arm of the first repeat packs against the core of the second repeat and vice versa. The structure of the core-interacting part of each arm consists of an N-terminal alpha-helix and a turn of 310 helix connected by a short beta-strand. The core consists of an Src homology 3-like five-stranded beta-barrel followed by a C-terminal alpha-helix and another short beta-strand. Each arm interacts with its partner core in a similar way, with the orientation of the N-terminal helix relative to the barrel varying slightly. There are also extensive interactions between the two barrels [PUBMED:12952983].
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|Cellular component||nucleus (GO:0005634)|
|Biological process||regulation of transcription, DNA-dependent (GO:0006355)|
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This clan covers the Tudor domain 'royal family' . This includes chromo, MBT, PWWP and tudor domains. The chromo domain is a comprised of approximately 50 amino acid residues. There are usually one to three Chromo domains found in a single protein. In some chromo domain containing proteins, a second related chromo domain has been found and is referred to as the Chromo-shadow domain. The structure of the Chromo and Chromo-shadow domains reveal an OB-fold, a fold found in a variety of prokaryotic and eukaryotic nucleic acid binding proteins. More specifically,the chromo-domain structure reveals a three beta strands that are packed against an alpha helix. Interestingly, a similar structure is found in the archaeal chromatin proteins (7kDa DNA-binding domain). These are sequence neutral DNA binding proteins. The DNA binding in these archaeal proteins is mediated through the triple stranded beta sheet. These archaeal domains are though to represent an ancestral chromo domain. Homologs of the chromo domain have been found in fission yeast, ciliated protozoa and all animal species, but appear to be absent in eubacteria, budding yeast and plants . The precise function of the chromo domain is unclear, but the chromo domain is thought to act as a targeting module for chromosomal proteins, although the chromosomal contexts and functional contexts being targeted vary. In all cases studies, the chromo domains are found in proteins that are involved in transcription regulation, positive and negative .
The clan contains the following 14 members:53-BP1_Tudor 7kD_DNA_binding Agenet Chromo Chromo_shadow DUF1325 DUF4537 MBT PWWP Rad9_Rad53_bind RBB1NT SMN TUDOR Tudor-knot
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Curation and family details
|Seed source:||Pfam-B_526 (Release 6.2)|
|Number in seed:||18|
|Number in full:||2104|
|Average length of the domain:||72.60 aa|
|Average identity of full alignment:||33 %|
|Average coverage of the sequence by the domain:||29.03 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||13|
|Download:||download the raw HMM for this family|
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There is 1 interaction for this family. More...
We determine these interactions using iPfam, which considers the interactions between residues in three-dimensional protein structures and maps those interactions back to Pfam families. You can find more information about the iPfam algorithm in the journal article that accompanies the website.
For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the MBT domain has been found. There are 159 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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